Quality control in the MRFIT local screening and clinic laboratory

Quality control was emphasized in the screening and clinic laboratory during the early stages of the trial to cover all aspects of screening, and in the later stages to cover local testing used to monitor the participant in the clinic and to guarantee collection of valid specimens to be shipped to the Central Laboratory. Special attention throughout the trial was focused on techniques for collection of specimens, since it was recognized that analytical results could not be better than the quality of the specimens. Training courses, on-site visits, and newsletters were used to sensitize the staff of the clinic laboratory about the necessity to follow protocol. Any monitoring evidence of carelessness, use of deteriorated supplies, failure to follow safety rules, and deviation from directions in the MRFIT Manual of Operations resulted in memoranda from the Coordinating Center or the Central Laboratory.